Processing of substrates (e.g., semiconductor, glass, etc.) for use in electronic devices is typically done in one or more processing chambers. The substrates may be moved between the processing chambers via a central transfer chamber. A slit valve connects the central transfer chamber to a processing chamber. A slit valve door may be employed to selectively block entrance of the slit valve, thereby sealing the transfer chamber from the process chamber. An insert may be positioned within the slit valve entrance to form a better seal for the slit valve door. The insert includes a tunnel that allows the substrate to pass between the transfer chamber and the process chamber. The chambers must be kept relatively free from particulates that may damage the substrates. In conventional systems, both the slit valve door and the insert are made of metal. The opening and closing of the slit valve door may cause the two metal surfaces to rub against each other, resulting in metal particles falling off the slit valve door and insert. Thus, to prevent the formation of metal particles, the slit valve door and the insert are oriented such that a gap exists between the slit valve door and the insert. A compressible seal, made of an elastomer, may be used to fill a portion of the gap and to create an air tight seal between the slit valve door and the insert.
Particulate byproducts, such as aluminum chloride, produced during substrate processing, may settle on the slit valve door as well as the exposed edge of the elastomer seal. The interior of the processing chamber is generally a higher temperature than the slit valve door/elastomer due to the heat given off during processing of the substrate in the processing chamber. As the particulate byproducts are attracted to cooler surfaces, the particulate byproducts are attracted to, and may settle on, the slit valve door and exposed edge of the elastomer seal. The closing and opening of the slit valve door causes the seal to compress and decompress, respectively. Over time, compressing and decompressing the seal may cause the particulate byproducts to flake off of the elastomer seal. The byproduct flakes may, in turn, contaminate the substrate processing. Thus, conventional seals must be replaced relatively frequently so that any accumulated byproducts do not become loose contaminates. Accordingly a need exists for an apparatus that allows the elastomer seal to be replaced less frequently.